Patient handling mattresses are known in the art which include at least two flexible material sheets, that together define a plenum chamber, with at least one sheet being perforated with small pinholes over at least a central surface area, and which open up directly to the interior of the plenum chamber. Such prior art mattresses are used by arranging the perforated sheet so that it faces an underlying fixed, generally planar support surface, such as a floor or table. When the mattress is charged with pressurized air, the escape of air under pressure through the pinholes acts initially to jack a load placed upon the mattress above the perforated flexible sheet, and thereby creates an air bearing of relatively small height between the underlying fixed, generally planar support surface and the perforated flexible sheet.
For example, in U.S. Pat. No. 4,517, 690, issued to Wegener, an air pallet is disclosed that is formed from upper and lower thin flexible film sheets sealed at their edges to form a plenum chamber. Wegener's air pallet functions to move a load with minimal friction over an underlying generally planar fixed support surface. The bottom thin flexible material sheet is perforated by small diameter perforations such as pin holes at the load imprint area.
In U.S. Pat. No. 5,561,873, issued to Weedling, provides an inflatable flexible pallet within which an array of structurally interrelated inflatable chambers are formed to support a load when inflated. The flexible pallet is configured to resist lateral and longitudinal shrinkage of the load support surface, as well as ballooning and hot dogging. Rotational instability is also reduced by providing a greater load surface support area.
In U.S. Pat. No. 6,073,291, issued to Davis, an inflatable medical patient transfer apparatus is disclosed that has a combination of transverse partition members and a raised perimeter section to reduce deleterious ballooning and uneven inflation as well as quick emergency deflation. Additional differentially inflatable patient rolling chambers are disclosed on the top of the transfer apparatus to provide assistance to medical personnel in beginning to roll patients reclining or lying upon the transfer apparatus, particularly in a deflated condition on a hospital bed.
All of the foregoing devices have needed to be cleaned after each use so as to prevent transmission of disease from their patient engaging surfaces, since they are all intended for multiple uses with multiple patients. Reusable mattresses need to have the material on their outer surfaces that contacts the patient be readily washable, and also be non-absorbent, since patients often experience loss of bodily fluids. None of the foregoing prior art transfer mattresses are appropriate for assuring single use by and personal to a single patient since all are susceptible to some cleaning that would mask the fact that there had been a prior use with the same or different patient. In the medical field, there is a continuing need to easily, safely and comfortably transport an injured person, hospital patient or injured person at the scene of an accident, using an air mattress that is not only suitable for only a single use, by a single patient, but also retains some evidence of that use so as to alert a second user to the mattresses “previously used” status.